“Brake-by-wire” brake systems are becoming increasingly widespread in the automotive industry. In addition to a brake master cylinder that can be actuated by the vehicle driver, such brake systems often comprise an electrically controllable pressure supply device, by means of which actuation of the wheel brakes or of the brake master cylinder takes place in the “brake-by-wire” operating mode. In order to give the vehicle driver a pleasant pedal feel in the “brake-by-wire” operating mode, the brake systems usually comprise a brake pedal feel simulation device. In these brake systems, the wheel brake can be actuated on the basis of electronic signals even without the active intervention of the vehicle driver. These electronic signals can be output by an electronic stability program or an active cruise control system, for example.
DE 101 47 181 A1,which is incorporated by reference, discloses an electrohydraulic brake-by-wire brake system having wheel brakes, an electrically controllable auxiliary pressure source and inlet and outlet valves capable of analog control. A method for activating the analog outlet valves is not disclosed.